Pulmonary lavage is easily obtainable and can be taken at various time intervals from the same animal (large such as dogs) without killing the animal. Pulmonary lavage contains lipoproteins, lipids, proteins, cells including macrophage and enzymes. The majority of these components are synthesized by the lung but some come via the pulmonary circulation, and some originate from bone marrow such as the macrophages. The alveolar macrophages are vital entities of the mammalian immune mechanism (in the latter, capacity macrophages depend upon plasma membrane activity for migration recognition, activation, phagocytosis and attachment to substrate tissue). Thus lavage can be used as a probe for early detection of lung damage, and of lung immune mechanism.